ROME (Reuters) - Italy's centre-left Democratic Party has increased its opinion poll lead, two surveys conducted just before a political crisis threatened to end Prime Minister Mario Monti's term early showed on Friday.
Elections are expected to be held early next year and the polls suggest the Democratic Party (PD) would be the largest party in parliament, but would probably have to seek allies from smaller leftist or centrist parties to be able to form a government.
A poll by the SWG institute for RAI television gave the PD 30.3 percent support, up from 30 percent a week earlier, higher than a 19.7 percent readout for the anti-establishment 5-Star Movement of comic Beppe Grillo.
A second poll by research group Demos and Pi for left-leaning daily La Repubblica gave the PD 37.8 percent support, an increase of more than ten points from a previous poll in September.
Silvio Berlusconi's centre-right PDL party, which triggered instability on Thursday by withholding its support for Monti's technocrat government in two parliamentary confidence votes, saw a slight drop in both polls, with the RAI one showing it on 13.8 percent and the Repubblica one putting it on 18.2 percent.
In the latter survey, Berlusconi emerged as one of the least popular leaders among 16 people graded, with an approval rating of just 20.8 percent. With 50.1 percent, PD leader Pier Luigi Bersani was among the most popular, as was Monti, with a 47.3 percent rating.
The surveys of just over 1,000 people each were conducted between Monday and Wednesday this week before Thursday's events in parliament which may see the election brought forward slightly.
The date of the vote remains uncertain pending a decision by President Giorgio Napolitano though Italy had in any case been expected to go to the polls no later than March.
The RAI poll gave Monti an approval rating of 33 percent, a fall of three points from a week earlier and the lowest level since the former European Commissioner was appointed just over a year ago to succeed Berlusconi at the height of the financial crisis.
Monti, who has been credited with restoring Italy's credibility with financial markets but who has angered voters with a series of tax hikes and spending cuts, has said he would be available to serve a second term if the election failed to produce a clear winner.
He has previously said he would not run himself but there has been speculation he may stand as a candidate.
A new centrist group headed by Ferrari chairman Luca Cordero di Montezemolo and seen as a possible vehicle for a Monti candidacy, saw its slim support decline further, dropping to 2.4 percent from 3.8 percent, according to the RAI poll.
(Reporting by Naomi O'Leary; Editing by Andrew Osborn)